Synthesis of ton framework type molecular sieves

ABSTRACT

A method is disclosed making a molecular of TON framework type having unique properties. The method uses 1,3,4-trimethylimidazolium cations as a structure directing agent and a combined source of silicon and aluminum selected from alumina-coated silica and aluminosilicate zeolites. The obtained molecular sieve can be used in processes for dewaxing paraffinic hydrocarbon feedstocks.

FIELD

This disclosure relates to an improved method for making molecularsieves having the TON framework structure and the use of molecularsieves so made in processes for catalytic conversion of hydrocarboncompounds.

BACKGROUND

Molecular sieve materials are classified by the Structure Commission ofthe International Zeolite Association according to the rules of theIUPAC Commission on Zeolite Nomenclature. According to thisclassification, framework type zeolites and other crystallinemicroporous crystalline materials, for which a structure has beenestablished, are assigned a three-letter code and are described in the“Atlas of Zeolite Framework Types”, Sixth Revised Edition, Elsevier(2007).

One known molecular sieve for which a structure has been established isthe material designated as TON, which is a molecular sieve having aunique one-dimensional 10-membered ring channel system. Examples of TONframework type molecular sieves include ISI-1, KZ-2, NU-10, Theta-1, andZSM-22. TON framework type materials are of significant commercialinterest because of their activity as catalysts in dewaxing ofparaffinic hydrocarbons.

According to the present disclosure, using 1,3,4-trimethylimidazoliumcations as a structure directing agent and aluminosilicate startingmaterials, it has now been found that TON-type molecular sieves can besynthesized by simpler processes and in shorter heating periods than waspreviously possible. Using these materials, TON-type molecular sievescan be made prepared having unique morphologies and physico-chemicalproperties. In addition, it is possible to produce TON-type molecularsieves with small crystal size.

SUMMARY

In a first aspect there is provided a method of synthesizing a molecularsieve of TON framework type, the method comprising: (1) forming areaction mixture comprising: (a) a combined source of silicon andaluminum, where the combined source of silicon and aluminum is analumina-coated silica, an aluminosilicate zeolite of FAU framework type,or a mixture thereof; (b) a structure directing agent (Q) comprising1,3,4-trimethylimidazolium cations; (c) a source of hydroxide ions; (d)water; and (e) seeds; and (2) subjecting the reaction mixture tocrystallization conditions sufficient to form crystals of the molecularsieve.

In a second aspect, there is provided a molecular sieve of TON frameworktype and, in its as-synthesized form, comprising1,3,4-trimethylimidazolium cations in its pores.

In a third aspect, there is provided a process for hydroisomerization ofa paraffinic hydrocarbon feedstock, the process comprising: contactingthe paraffinic hydrocarbon feedstock at hydroisomerization conditionswith hydrogen and a catalyst comprising a molecular sieve of TONframework type, and yielding a product having an increase in branchedhydrocarbons relative to hydrocarbon feedstock; wherein the catalystfurther comprises 0.01 to 10% by weight of a noble metal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a powder X-ray diffraction (XRD) pattern of the calcinedmolecular sieve obtained in Example 1.

FIGS. 2(A) and 2(B) show illustrative Scanning Electron Micrograph (SEM)images of the product of Example 1 at various magnifications.

FIG. 3 shows a powder XRD pattern of the calcined molecular sieveobtained in Example 2.

FIGS. 4(A) and 4(B) show illustrative SEM images of the product ofExample 2 at various magnifications.

FIG. 5 shows a powder XRD pattern of the calcined molecular sieveobtained in Example 3.

FIGS. 6(A) and 6(B) show illustrative SEM images of the product ofExample 3 at various magnifications.

FIG. 7 shows a powder XRD pattern of the calcined molecular sieveobtained in Example 4.

FIGS. 8(A) and 8(B) show illustrative SEM images of the product ofExample 4 at various magnifications.

FIG. 9 shows a powder XRD pattern of the calcined molecular sieveobtained in Example 5.

FIG. 10 shows an illustrative SEM image of the product of Example 5.

FIG. 11 shows a powder XRD pattern of the calcined molecular sieveobtained in Example 6.

FIGS. 12(A) and 12(B) show illustrative SEM images of the product ofExample 6 at various magnifications.

FIG. 13 is a plot of conversion as a function of temperature forn-decane conversion over the catalyst of Example 5.

FIG. 14 is a plot of conversion versus yield for n-decane conversionover the catalyst of Example 5.

FIG. 15 is plot illustrating the distribution of methylnonane isomers asa function of conversion for n-decane conversion over the catalyst ofExample 5.

FIG. 16 is a plot of conversion as a function of temperature forn-decane conversion over the catalyst of Example 6.

FIG. 17 is a plot of conversion versus yield for n-decane conversionover the catalyst of Example 6.

FIG. 18 is plot illustrating the distribution of methylnonane isomers asa function of conversion for n-decane conversion over the catalyst ofExample 6.

DETAILED DESCRIPTION Definitions

The term “framework type” as used herein has the meaning described inthe “Atlas of Zeolite Framework Types” by Ch. Baerlocher, L. B. McCuskerand D. H. Olson (Elsevier, Sixth Revised Edition, 2007).

The term “as-synthesized” refers to a molecular sieve in its form aftercrystallization, prior to removal of the structure directing agent.

The term “Cn” hydrocarbon means a hydrocarbon compound having n numberof carbon atom(s) per molecule. The term “Cn+” hydrocarbon means ahydrocarbon compound having n or more than n carbon atom(s) permolecule. The term “Cn−” hydrocarbon means a hydrocarbon compound havingno more than n carbon atom(s) per molecule.

The term “SiO₂/Al₂O₃ molar ratio” may be abbreviated as “SAR”.

Synthesis of the Molecular Sieve

A molecular sieve of TON framework type can be synthesized by: (1)forming a reaction mixture comprising: (a) a combined source of siliconand aluminum, where the combined source of silicon and aluminum is analumina-coated silica, an aluminosilicate zeolite of FAU framework type,or a mixture thereof; (b) a structure directing agent (Q) comprising1,3,4-trimethylimidazolium cations; (c) a source of hydroxide ions; (d)water; and (e) seeds; and (2) subjecting the reaction mixture tocrystallization conditions sufficient to form crystals of the molecularsieve.

The reaction mixture can have a composition, in terms of molar ratios,within the ranges set forth in Table 1:

TABLE 1 Broadest Secondary SiO₂/Al₂O₃  30 to 170  35 to 130 Q/SiO₂ 0.03to 0.50 0.04 to 0.30 OH/SiO₂ 0.05 to 1.00 0.10 to 0.50 H₂O/SiO₂  5 to100 10 to 50wherein Q comprises 1,3,4-trimethylimidazolium cations.

The alumina-coated silica can have a SiO₂/Al₂O₃ molar ratio of at least30 (e.g., 30 to 170, 35 to 100, 50 to 100, 60 to 80, or 100 to 170).Alumina-coated silicas may be obtained from Nalco. The aluminosilicatezeolite of FAU framework type can be zeolite Y. The aluminosilicatezeolite can have a SiO₂/Al₂O₃ molar ratio of at least 30 (e.g., 30 to100, or 60 to 80). Examples of suitable aluminosilicate zeolites includeY zeolites CBV720, CBV760, and CBV780, available commercially fromZeolyst International. The combined source of silicon and aluminum maybe used as the sole or predominant source of silicon and aluminum in thereaction mixture.

The reaction mixture can contain a separate source of silicon. Ifpresent, suitable sources of silicon include colloidal silica,precipitated silica, fumed silica, alkali metal silicates, andtetraalkyl orthosilicates.

The source of hydroxide ions can be an alkali metal hydroxide. Thealkali metal can be lithium, sodium, potassium, or a mixture thereof.However, this component can be omitted so long as the equivalentbasicity is maintained. The structure directing agent can be used toprovide hydroxide ion. If present, the molar ratio of alkali metalcation/SiO₂ can be in a range of from 0.05 to 1.00 (e.g., 0.05 to 0.50).

The structure directing agent (Q) comprises 1,3,4-trimethylimidazoliumcations, represented by the following structure (1):

Suitable sources of Q include the hydroxides, chlorides, bromides,and/or other salts of the quaternary ammonium compound.

The reaction mixture also contains seeds, typically of a TON frameworktype molecular sieve, desirably in an amount of from 0.01 to 10,000 ppmby weight (e.g., 100 to 5000 ppm by weight) of the reaction mixture.Seeding can be advantageous to improve selectivity for TON and/or toshorten the crystallization process.

Crystallization of the desired molecular sieve from the above reactionmixture can be carried out under either static, tumbled or stirredconditions in a suitable reactor vessel, such as for examplepolypropylene jars or Teflon-lined or stainless-steel autoclaves, at atemperature of from 120° C. to 200° C. (e.g., 135° C. to 180° C.) for atime sufficient for crystallization to occur at the temperature used,e.g., from about 1 day to 10 days (e.g., 2 days to 7 days).Crystallization is usually conducted under pressure in an autoclave sothat the reaction mixture is subject to autogenous pressure.

Once the desired molecular sieve crystals have formed, the solid productcan be separated from the reaction mixture by standard mechanicalseparation techniques such as centrifugation or filtration. Therecovered crystals are water-washed and then dried, for several secondsto a few minutes (e.g., 5 seconds to 10 minutes for flash drying) orseveral hours (e.g., 4 hours to 24 hours for oven drying at 75° C. to150° C.), to obtain the as-synthesized molecular sieve crystals. Thedrying step can be performed under vacuum or at atmospheric pressure.

As a result of the crystallization process, the recovered crystallinemolecular sieve product contains within its pores at least a portion ofthe structure directing agent used in the synthesis.

The as-synthesized molecular sieve may be subjected to thermaltreatment, ozone treatment, or other treatment to remove part or all ofthe structure directing agent used in its synthesis. Removal ofstructure directing agent may be carried out using thermal treatment(e.g., calcination) in which the as-synthesized material is heated in anatmosphere selected from air, nitrogen, or a mixture thereof at atemperature sufficient to remove part or all of the structure directingagent. While sub-atmospheric pressure may be used for the thermaltreatment, atmospheric pressure is desired for reasons of convenience.The thermal treatment may be performed at a temperature at least 370° C.(e.g., 400° C. to 700° C.) for at least a minute and generally notlonger than 20 hours (e.g., 1 to 8 hours).

The TON-type molecular sieve (where part or all of the structuredirecting agent is removed) may be combined with a hydrogenating metalcomponent. The hydrogenating metal component may be selected frommolybdenum, tungsten, rhenium, nickel, cobalt, chromium, manganese, or anoble metal, such as platinum or palladium where ahydrogenation-dehydrogenation function is to be performed. Suchhydrogenating metal components may be incorporated into the compositionby way of one or more of the following processes: co-crystallizing;ion-exchanging into the composition; impregnating therein or physicallyadmixing therewith. The amount of metal can be in a range of 0.001 to20% by weight (0.01 to 10% by weight, or 0.5 to 2.0% by weight) ofcatalyst.

Once the molecular sieve has been synthesized, it can be formulated intoa catalyst composition by combination with another material resistant tothe temperatures and other conditions employed in organic conversionprocesses. Such resistant materials may be selected from activematerials, inactive materials, synthetic zeolites, naturally occurringzeolites, inorganic materials, or a mixture thereof. Examples of suchresistant materials may be selected from clays, silica, titania, metaloxides such as alumina, or a mixture thereof. The inorganic material maybe either naturally occurring, or in the form of gelatinous precipitatesor gels, including mixtures of silica and metal oxides. Use of aresistant material in conjunction with the molecular sieve, i.e.,combined therewith or present during synthesis of the as-synthesizedmaterial, which crystal is active, tends to change the conversion and/orselectivity of the catalyst in certain organic conversion processes.Inactive resistant materials suitably serve as diluents to control theamount of conversion in a given process so that products can be obtainedin an economic and orderly manner without employing other means forcontrolling the rate of reaction. These materials may be incorporatedinto naturally occurring clays (e.g., bentonite and kaolin) to improvethe crush strength of the catalyst under commercial operatingconditions. The inactive resistant materials (i.e., clays, oxides, etc.)function as binders for the catalyst. A catalyst having good crushstrength can be beneficial because in commercial use it is desirable toprevent the catalyst from breaking down into powder-like materials.

Naturally occurring clays which may be composited with the molecularsieve include the montmorillonite and kaolin family, which familiesinclude the subbentonites, and the kaolins commonly known as Dixie,McNamee, Ga. and Florida clays or others in which the main mineralconstituent is halloysite, kaolinite, dickite, nacrite, or anauxite.Such clays may be used in the raw state as originally mined or initiallysubjected to calcination, acid treatment or chemical modification.

Binders useful for compositing with the molecular sieve also includeinorganic oxides selected from silica, zirconia, titania, magnesia,beryllia, alumina, or a mixture thereof.

In addition to the foregoing materials, the molecular sieve may becomposited with a porous matrix material such as silica-alumina,silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia,silica-titania as well as ternary compositions such assilica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesiaand silica-magnesia-zirconia.

The relative proportions of molecular sieve and inorganic oxide matrixmay vary widely, with the molecular sieve content ranging from 1 to 95%by weight (e.g., 20 to 90% by weight) of the composite.

The catalyst is employed in the conventional manner in the form of, forexample, spheres or extrudates.

Characterization of the Molecular Sieve

In its as-synthesized and anhydrous form, the molecular sieve can have achemical composition, in terms of molar ratios, within the ranges setforth in Table 2:

TABLE 2 Broadest Secondary SiO₂/Al₂O₃ 30 to 100  35 to 80  Q/SiO₂ >0 to≤0.1 >0 to ≤0.1wherein Q comprises 1,3,4-trimethylimidazolium cations.

The TON framework type molecular sieves prepared as described herein canhave a small crystal size. The crystal size is based on individualcrystals (including twinned crystals) but does not includeagglomerations of crystals. Crystal size is the length of longestdiagonal of the three-dimensional crystal. Direct measurement of thecrystal size can be performed using microscopy methods, such as SEM andTEM. For example, measurement by SEM involves examining the morphologyof materials at high magnifications (typically 1000× to 10,000×). TheSEM method can be performed by distributing a representative portion ofthe molecular sieve powder on a suitable mount such that individualparticles are reasonably evenly spread out across the field of view at1000× to 10,000× magnification. From this population, a statisticallysignificant sample of random individual crystals (e.g., 50 to 200) areexamined and the longest diagonal of the individual crystals aremeasured and recorded. (Particles that are clearly large polycrystallineaggregates should not be included the measurements.) Based on thesemeasurements, the arithmetic mean of the sample crystal sizes iscalculated.

The TON framework type molecular sieves synthesized as described hereinare characterized by their powder X-ray diffraction (XRD) pattern.Powder XRD patterns representative of TON framework type molecularsieves can be referenced in “Collection of Simulated XRD Powder Patternsfor Zeolites” by M. M. J. Treacy and J. B. Higgins (Elsevier, FifthRevised Edition, 2007).

The X-ray diffraction data reported herein were collected by standardtechniques using copper K-alpha radiation. Minor variations in thediffraction pattern can result from variations in the mole ratios of theframework species of the particular sample due to changes in latticeconstants. In addition, sufficiently small crystals will affect theshape and intensity of peaks, leading to significant peak broadening.Minor variations in the diffraction pattern can also result fromvariations in the organic compound used in the preparation. Calcinationcan also cause minor shifts in the XRD pattern. Notwithstanding theseminor perturbations, the basic crystal lattice structure remainsunchanged.

Hydroisomerization of Paraffinic Hydrocarbon Feedstocks

The present molecular sieve is suitable for use as a catalyst inhydroisomerizing paraffinic hydrocarbon feedstocks when contacted by thecatalyst with hydrogen at hydroisomerization conditions to yield aproduct having an increase in branched hydrocarbons relative tohydrocarbon feedstock.

Hydroisomerization conditions include a temperature of from 200° C. to450° C. (e.g., 250° C. to 400° C.), a pressure of from 0.5 to 20 MPa(e.g., 1 to 15 MPa), a liquid hourly space velocity of from 0.1 to 10h⁻¹ (e.g., 0.5 to 5 h⁻¹), and a hydrogen circulation rate of from 35.6to 1781 Nm³/m³ (e.g., 890 to 1424 Nm³/m³).

The hydrocarbon feedstock is not limited to a specific type if thehydrocarbon feedstock includes n-C8+ hydrocarbons (e.g., n-C10+hydrocarbons, or n-C15+ hydrocarbons). More specifically, examples ofsuch hydrocarbon feedstocks include relatively light distilledfractions, such as kerosenes and jet fuels; and high boiling pointstocks, such as fuel fractions or wax fractions derived from any type ofcrude oils, atmospheric distillation residues (atmospheric residues),vacuum tower residues, vacuum distillation residues (vacuum residues),cycle stocks, syncrudes (e.g., shale oil, tar oil, and the like), gasoil, vacuum gas oil, foots oil, and Fischer-Tropsch synthetic oil; andother heavy oils.

EXAMPLES

The following illustrative examples are intended to be non-limiting.

Example1

In a 23 mL Teflon autoclave 3.96 g of an aqueous solution of1,3,4-trimethylimidazolium hydroxide (0.98 mmol OH⁻/g) was mixed with5.21 g of deionized water. Then, 1.0 g of CBV780 Y zeolite (SAR=80) wasadded, followed by seeds of zeolite TON, and mixed well. The sealedautoclave was heated at 170° C. for 3 days with rotation at 43 rpm. Thematerial was recovered by filtration and washed with copious amounts ofwater and finally dried in air at 85° C.

The material was calcined in air by placing a thin bed of material in acalcination dish and heated in a muffle furnace from room temperature to120° C. at a rate of 1° C./minute and held at 120° C. for 2 hours. Then,the temperature was ramped up to 540° C. at a rate of 1° C./min and heldat 540° C. for 5 hours. The temperature was ramped up again at 1°C./minute to 595° C. and held 595° C. for 5 hours. The material was thenallowed to cool to room temperature.

The powder XRD pattern of the calcined material is shown in FIG. 1 andindicates that the material is a TON framework zeolite. FIGS. 2(A) and2(B) show illustrative SEM images of the product at variousmagnifications. As shown, the crystals have a columnar morphology withan average length greater than 1 μm, an average width of about 0.5 μm,and an average thickness of less than 0.1 μm.

Example 2

In a 23 mL Teflon autoclave 0.72 g of an aqueous solution of1,3,4-trimethylimidazolium hydroxide (0.98 mmol OH⁻/g) was mixed with0.17 g of LiOH·H₂O and 7.22 g of deionized water. Then, 4.0 g of analumina-coated silica (SAR=100, 26.5% solids, Nalco) was added, followedby seeds of zeolite TON, and mixed well. The sealed autoclave was heatedat 170° C. for 3 days with rotation at 43 rpm. The material wasrecovered by filtration and washed with copious amounts of water andfinally dried in air at 85° C.

The as-synthesized material was calcined according to the methoddescribed in Example 1.

The powder XRD pattern of the calcined material is shown in FIG. 3 andindicates that the material is a TON framework zeolite. FIGS. 4(A) and4(B) show illustrative SEM images of the product at variousmagnifications. As shown, the crystals were in the form of bundles ofneedles having a mean length greater than 1 μm and a mean thickness ofless than 0.1 nm.

Example 3

In a 23 mL Teflon autoclave 0.72 g of an aqueous solution of1,3,4-trimethylimidazolium hydroxide (0.98 mmol OH⁻/g) was mixed with0.096 g of LiOH·H₂O, 1.76 g of 1 M KOH and 5.54 g of deionized water.Then, 4.0 g of an alumina-coated silica (SAR=100, 26.5% solids, Nalco)was added, followed by seeds of zeolite TON, and mixed well. The sealedautoclave was heated at 170° C. for 3 days with rotation at 43 rpm. Thematerial was recovered by filtration and washed with copious amounts ofwater and finally dried in air at 85° C.

The as-synthesized material was calcined according to the methoddescribed in Example 1.

The powder XRD pattern of the calcined material is shown in FIG. 5 andindicates that the material is a TON framework zeolite. FIGS. 6(A) and6(B) show illustrative SEM images of the product at variousmagnifications. As shown, the crystals were in the form of columnarbundled needles with an average length greater than 1 μm, an averagewidth of about 0.1 μm, and an average thickness of less than 100 nm.

Example 4

In a 23 mL Teflon autoclave 1.91 g of an aqueous solution of1,3,4-trimethylimidazolium hydroxide (0.98 mmol OH⁻/g) was mixed with0.085 g of LiOH·H₂O and 3.42 g of deionized water. Then 1.0 g of CBV780Y zeolite (SAR=80) was added, followed by seeds of zeolite TON, andmixed well. The sealed autoclave was heated at 150° C. for 3 days withrotation at 43 rpm. The material was recovered by filtration and washedwith copious amounts of water and finally dried in air at 85° C.

The as-synthesized material was calcined according to the methoddescribed in Example 1.

The powder XRD pattern of the calcined material is shown in FIG. 7 andindicates that the material is a TON framework zeolite. FIGS. 8(A) and8(B) show illustrative SEM images of the product at variousmagnifications. As shown, the crystals were in the form of irregularlyshaped platelets with mean dimensions of less than 1 μm×1 μm and a meanthickness of less than 50 nm.

Example 5

In a 125 mL Teflon autoclave 5.38 g of an aqueous solution of1,3,4-trimethylimidazolium hydroxide (0.88 mmol OH⁻/g) was mixed with27.24 g of 1 M KOH and 21.2 g of deionized water. Then, 21.0 g of analumina-coated silica (SAR=35; 24.5% solids, Nalco) was added and then7.02 g of LUDOX® AS-30 colloidal silica, followed by seeds of zeoliteTON, and mixed well. The sealed autoclave was heated at 175° C. for 2days with rotation at 43 rpm. The material was recovered by filtrationand washed with copious amounts of water and finally dried in air at 85°C.

The as-synthesized material was calcined according to the methoddescribed in Example 1.

The powder XRD pattern of the calcined material is shown in FIG. 9 andindicates that the material is a TON framework zeolite. FIG. 10 shows anillustrative SEM image of the product. As shown, crystals were in theform of a bundle of fibrous needles of small crystal size.

The calcined material was then converted to the ammonium form by heatingin a solution of ammonium nitrate (typically, 1 g NH₄NO₃/1 g zeolite in10 mL of H₂O at 85° C. for at least 3 hours). The material was thenfiltered. This was repeated twice for a total of 3 exchanges. At theend, the material was washed with deionized water to a conductivity ofless than 100 μS/cm dried in air at 85° C.

The acid site density was characterized using n-propylaminetemperature-programmed desorption (TPD) and found to be 522 pmol H⁺/g.

The nitrogen micropore volume was found to be 0.095 cm³/g (t-plotanalysis) and the BET surface area was 232.6 m²/g.

The SAR was of the material found to be 44.7, according to InductivelyCoupled Plasma-Mass Spectrometry (ICP-MS).

For the palladium exchange to 0.5 wt. % Pd, 1.6 g of NH₄ ⁺ form materialwas combined with 15.3 g of deionized water and 7.0 g of 0.156 N NH₄OHsolution followed by 1.6 g of palladium solution that was prepared bycombining 0.36 g of Pd(NH₃)₄(NO₃)₂ in 21 g of deionized water and 3 g of0.148N NH₄OH solution. The pH was then checked, and if necessary,adjusted to 10 by adding concentrated ammonium hydroxide dropwise untila pH of 10 was reached. After standing at room temperature for 3 days,the pH was checked again and if necessary readjusted to 10 and allowedto sit for 1 more day. The material was recovered by filtration, washedwith deionized water, and dried in air overnight at 85° C. The Pd formmaterial was calcined in dry air by heating at 1° C./minute ramp to 120°C. and held for 180 minutes at 120° C., and then heated at 1° C./minuteto 482° C. and held for 180 minutes at 482° C. Finally, the material waspelletized at 5 kpsi, crushed and sieved to 20-40 mesh.

Example 6

In a 125 mL Teflon autoclave 5.37 g of an aqueous solution of1,3,4-trimethylimidazolium hydroxide (0.88 mmol OH⁻/g) was mixed with27.18 g of 1 M KOH and 20.1 g of DI water. Then 29.0 g of analumina-coated silica (SAR=80; 26.9% solids, Nalco) was added, followedby seeds of zeolite TON, and mixed well. The sealed autoclave was heatedat 175° C. for 2 days at a rotation of 43 rpm. The material wasrecovered by filtration and washed with copious amounts of water andfinally dried in air at 85° C.

The material was calcined and converted to ammonium form according tothe method described in Example 5.

The powder XRD pattern of the calcined material is shown in FIG. 11 andindicates that the material is a TON framework zeolite. FIGS. 12(A) and12(B) show illustrative SEM images of the product at variousmagnifications. As shown, the crystals have a somewhat lamellarmorphology with a very small crystal size.

The acid site density was characterized using n-propylamine TPD andfound to be 340 pmol H⁺/g.

The nitrogen micropore volume was found to be 0.10 cm³/g (t-plotanalysis) and the BET surface area was 240.1 m²/g.

The SAR was of the material found to be 70.1, according to ICP-MS.

Exchange to 0.5 wt. % Pd was conducted according to the method describedin Example 5.

Example 7 Hydroconversion of n-Hexadecane

0.5 g of the palladium exchanged sample was loaded in the center of a 23inch-long×0.25 inch outside diameter stainless steel reactor tube withalundum loaded upstream of the catalyst for pre-heating the feed (totalpressure of 1200 psig; down-flow hydrogen rate of 160 mL/minute, whenmeasured at 1 atmosphere pressure and 25° C.; down-flow liquid feed rateof 1 mL/hour). All materials were first reduced in flowing hydrogen atabout 315° C. for 1 hour. Products were analyzed by on-line capillarygas chromatography (GC) once every thirty minutes. Raw data from the GCwas collected by an automated data collection/processing system andhydrocarbon conversions were calculated from the raw data.

Conversion was defined as the amount of n-hexadecane reacted to produceother products (including iso-C16 isomers). Yields were expressed asweight percent of products other than n-C16 and included iso-C16 as ayield product. The results at 96% conversion are reported in Table 3.

TABLE 3 Summary of n-Hexadecane Hydroconversion at 96% ConversionCatalyst Example 5 Example 6 Selectivity 64.4 67.7 Temperature [° F.]514.5 522.5 C4- Cracking [wt. %] 7.3 4.3

Example 8 Hydroconversion of n-Decane

For catalytic testing, 0.5 g of the Pd catalyst (weight of thedehydrated sample as determined by thermogravimetric analysis at 600°C.) was loaded in the center of a 23 inch-long×0.25 inch outsidediameter stainless steel reactor tube with alundum loaded upstream ofthe catalyst for preheating the feed (a total pressure of 1200 psig; adown-flow hydrogen rate of 12.5 mL/minute, when measured at 1 atmospherepressure and 25° C.; and a down-flow liquid feed rate of 1 mL/hour). Thecatalyst was first reduced in flowing hydrogen at 315° C. for 1 hour.The reaction was carried out at a temperature of from 230° C. to 310° C.Products were analyzed by on-line capillary GC approximately once everysixty minutes. Raw data from the GC was collected by an automated datacollection/processing system and hydrocarbon conversions were calculatedfrom the raw data. Conversion is defined as the amount n-decane reactedin mol % to produce other products (including iso-C10). The yield ofiso-C10 is expressed as mole percent of products other than n-decane.The yield of cracking products (smaller than C10) is expressed as molepercent of n-decane converted to cracking products. The results areshown in FIG. 13 through FIG. 18, and the key catalytic performancemetrics are in Table 4.

The Modified Constraint Index (Cl*) was calculated as the ratio of2-methylnonane to 5-methylnonane at the total isomer yield of around 5%,and is shown in Table 4.

TABLE 4 Summary of n-Decane Hydroconversion at Maximum Total IsomerYield Catalyst Example 5 Example 6 Temp. at Maximum Isomer Yield [° F.]500 520 Maximum Total Isomer Yield [%] 37.9 55.3 Mono-Isomer Yield [%]36.5 53.2 Cracking [%] 38.3 33.0 Conversion [%] 76.2 88.3 CI* 12.3 16.0

1. A method of synthesizing a molecular sieve of TON framework type, themethod comprising: (1) forming a reaction mixture comprising: (a) acombined source of silicon and aluminum, where the combined source ofsilicon and aluminum is an alumina-coated silica, an aluminosilicatezeolite of FAU framework type, or a mixture thereof; (b) a structuredirecting agent (Q) comprising 1,3,4-trimethylimidazolium cations; (c) asource of hydroxide ions; (d) water; and (e) seeds; and (2) subjectingthe reaction mixture to crystallization conditions sufficient to formcrystals of the molecular sieve.
 2. The method of claim 1, wherein thereaction mixture has a composition, in terms of molar ratios, asfollows: SiO₂/Al₂O₃  30 to 170 Q/SiO₂ 0.03 to 0.50 OH/SiO₂ 0.05 to 1.00H₂O/SiO₂   5 to
 100.


3. The method of claim 1, wherein the reaction mixture has acomposition, in terms of molar ratios, as follows: SiO₂/Al₂O₃  35 to 130Q/SiO₂ 0.04 to 0.30 OH/SiO₂ 0.10 to 0.50 H₂O/SiO₂  10 to
 50.


4. The method of claim 1, wherein the aluminosilicate zeolite of FAUframework type is zeolite Y.
 5. The method of claim 1, wherein thesource of hydroxide ions comprises an alkali metal hydroxide.
 6. Themethod of claim 5, wherein the alkali metal is lithium, sodium,potassium, or a mixture thereof.
 7. The method of claim 6, wherein amolar ratio of alkali metal cation/SiO₂ is in a range of from 0.1 to1.0.
 8. The method of claim 1, wherein the seeds comprise a molecularsieve of TON framework type.
 9. The method of claim 1, wherein thereaction mixture comprises from 0.01 ppm by weight to 10,000 ppm byweight of seeds.
 10. The method of claim 1, wherein the reaction mixturefurther comprises a separate source of silicon.
 11. The method of claim10, wherein the separate source of silicon comprises colloidal silica,precipitated silica, fumed silica, an alkali metal silicate, atetraalkyl orthosilicate, or a mixture thereof.
 12. The method of claim1, wherein the crystallization conditions include a temperature of from125° C. to 200° C. and a time of from 1 day to 10 days.
 13. A molecularsieve of TON framework type and, in its as-synthesized form, comprising1,3,4-trimethylimidazolium cations in its pores.
 14. The molecular sieveof claim 13, having a molar ratio of SiO₂/Al₂O₃ in a range of from 30 to100.
 15. The molecular sieve of claim 13, having a molar ratio ofSiO₂/Al₂O₃ in a range of from 35 to
 80. 16. A process forhydroisomerization of a paraffinic hydrocarbon feedstock, the processcomprising: contacting the paraffinic hydrocarbon feedstock athydroisomerization conditions with hydrogen and a catalyst comprising amolecular sieve of TON framework type, and yielding a product having anincrease in branched hydrocarbons relative to hydrocarbon feedstock;wherein the catalyst further comprises 0.01 to 10% by weight of a noblemetal.
 17. The process of claim 16, wherein the paraffinic hydrocarbonfeedstock comprises n-C8+ hydrocarbons.
 18. The process of claim 16,wherein the molecular sieve has a molar ratio of SiO₂/Al₂O₃ in a rangeof from 30 to
 100. 19. The process of claim 16, wherein the molecularsieve has a molar ratio of SiO₂/Al₂O₃ in a range of from 35 to
 80. 20.The process of claim 16, wherein the noble metal comprises platinum,palladium, or a mixture thereof.
 21. The process of claim 16, whereinthe hydroisomerization conditions include a temperature of from 200° C.to 450° C., a pressure of from 0.5 to 20 MPa, a liquid hourly spacevelocity of from 0.1 to 10 h⁻¹, and a hydrogen circulation rate of from35.6 to 1781 Nm³/m³.